Double-sided fasteners

ABSTRACT

A method for forming a double-sided loop strap includes: receiving a continuous longitudinal strip of loop material including a strip-form base bearing a field of upstanding loops on a fastening side of the strip bounded by opposite longitudinal edges, folding each of the longitudinal edges away from the fastening side, such that the base overlaps itself, and securing the folded edges in place by permanently bonding together overlapped areas of the base to form the double-sided loop strap.

TECHNICAL FIELD

This invention relates to double-sided loop straps, such as used intouch fastener products.

BACKGROUND

Double-sided fabrics are widely used in a variety of markets including,for example, the medical, apparel and sports markets. For applicationsin which a double-sided fabric is to engage with touch fasteners, eitherside may be constructed to be hook engageable. Such products are usefulin medical and sports markets for applications such as straps, which maysupport medical devices on a patient, or in braces that may be wrappedaround body parts, such as elbows or knees as support. In someapplications, these double-sided, hook compatible straps are intendedfor skin contact, and must therefore be comfortable to the touch andbreathable (i.e., air permeable) to some degree.

SUMMARY

One aspect of the invention features a method for forming a double-sidedloop strap, including: receiving a continuous longitudinal strip of loopmaterial including a strip-form base bearing a field of upstanding loopson a fastening side of the strip bounded by opposite longitudinal edges,folding each of the longitudinal edges away from the fastening side,such that the base overlaps itself, and securing the folded edges inplace by permanently bonding together overlapped areas of the base toform the double-sided loop strap. The bonding forms discrete bondedregions of the base surrounded by unbonded area, the bonded regionsincluding a row of the bonded regions extending along and overlapping atleast one of the folded edges, and a pattern of bonded regionssurrounded by engageable loops on either side of the strap.

In some examples, folding each of the longitudinal edges includesfolding the edges sufficiently inward to meet on one side of the strap.In some implementations, the row of bonded regions forms a seam alongthe longitudinal edges.

In some applications, the bonded regions of the row of bonded regionsare shaped to form visually recognizable graphics.

In some cases, a density of the pattern of bonded regions varieswidthwise and/or lengthwise along the strap.

In some embodiments, the density of the pattern of bonded regionsgradually increases from the center area of the strap in an outboarddirection.

In some examples, permanently bonding includes heat staking overlappedareas of the base.

Another aspect of the invention features a double-sided loop strap,including: a first side including a first loop-bearing surface, and asecond side opposite the first side, the second side including a secondloop-bearing surface and an adjacent grip area covered by a gripmaterial forming an exposed grip surface, where the exposed grip surfaceis recessed below the second loop-bearing surface.

In some examples, the grip area includes a longitudinally continuouslane bounded on both sides by loop material.

In some cases, the grip surface features protrusions of the gripmaterial.

In some applications, the first loop-bearing surface is of a loopmaterial forming one broad side of the strap opposite the grip surface,and the second loop-bearing surface is of a loop material having alongitudinal edge adjacent to the grip surface and secured by the gripmaterial.

In some embodiments, the grip area has a lateral extent of between 10and 90 percent of an overall width of the strap.

In some examples, the first loop-bearing surface is of a loop materialforming one broad side of the strap opposite the grip surface, and thesecond loop-bearing surface is of a loop material having an edgebounding a hole through the loop-bearing surface.

In some implementations, the grip material has a dynamic coefficient offrication that is greater than about 0.3.

Yet another aspect of the invention features a double-sided loop strap,including: a first side including a first loop-bearing surface, and asecond side opposite the first side, the second side including a secondloop-bearing surface and an adjacent grip area covered by a gripmaterial forming an exposed grip surface, where the exposed grip surfaceis bounded by an edge of the second loop-bearing surface.

In some examples, the edge is a continuous longitudinal edge of thesecond loop-bearing surface.

In some applications, the edge bounds a hole through the secondloop-bearing surface.

In some cases, the grip material extends underneath and bonds the edge.

In some implementations, the grip surface is recessed below the secondloop-bearing surface.

In some embodiments, the grip material includes a foaming agent.

In some examples, a portion the grip surface is at least level with thesecond loop-bearing surface.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A is cross-sectional view of a double-sided loop strap.

FIG. 1B is a top view of the double-sided loop strap of FIG. 1A.

FIG. 1C is a cross-sectional view of a strip of loop material withfolded edges.

FIG. 2A is a top view of a first example double-sided loop strapfeaturing an irregular pattern of discrete bonded regions.

FIG. 2B is a top view of a second example double-sided loop strapfeaturing an irregular pattern of discrete bonded regions.

FIG. 3 is a top view of a double-sided loop strap featuring discretebonded regions shaped as visually recognizable graphics.

FIG. 4A is a cross-sectional view of a composite double-sided loopstrap.

FIG. 4B is a top view of the composite double-sided loop strap of FIG.4A.

FIG. 5A is a cross-sectional view of a double-sided loop strap featuringa non-slip surface.

FIG. 5B is a top view of the double-sided loop strap of FIG. 5A.

FIG. 5C is a cross-sectional view of a strip of loop material withfolded edges carrying a deposit of resinous grip material.

FIG. 6A is a cross-sectional view of a double-sided loop strap featuringa non-slip surface with upstanding treads.

FIG. 6B is a top view of the double-sided loop strap of FIG. 6A.

FIGS. 7A and 7B are cross-sectional views of a double-sided loop strapfeaturing a non-slip surface formed from a resinous, foam activated gripmaterial.

FIG. 8 is a perspective view of an adjustable cinch strap featuring adouble-sided loop strap providing a non-slip surface.

FIG. 9A is a cross-sectional view of a double-sided loop strap featuringmultiple discrete non-slip surfaces.

FIG. 9B is a top view of the double-sided loop strap of FIG. 9A.

FIG. 10A is a schematic representation of a first method and apparatusfor making a double-sided loop strap.

FIGS. 10B-10E are schematic representations of a second method andapparatus for making a double-sided loop strap featuring a non-slipsurface.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

FIGS. 1A and 1B show an example double-sided loop strap 100 having afront side 104 and a back side 102, each of which features a field ofupstanding, hook compatible loops 106. Note that the convention of“front” and “back” is used herein for discussion purposes only, and isnot intended to carry any significant meaning that would affect thescope of the present disclosure. In this example, loop strap 100 is amulti-layer construction fashioned from a preform elongated strip ofloop material 108 defining a pair of free longitudinal edges 110 (seeFIG. 1C). Edges 110 are folded over to form two inwardly facing arms 112meeting edge-to-edge near a center area of the strip. As shown, strip108 features a flexible base 114 bearing a field of upstanding loops 106on one side. In particular, the loops extend from an outward surface ofthe base which is bounded by the free longitudinal edges.

The structure and physical properties of strip 108 may vary in differentimplementations. For example, the strip can have a woven loop structure(e.g., having napped or un-napped loops), a knitted loop structureand/or a non-woven loop structure. The materials used to manufacturestrip 108 may also vary. For example, nylon, polyester, polypropylene,and/or aramid fibers can be used to manufacture the preform loop strip.Though not exhaustive, the foregoing examples illustrate the numerousdifferent types of hook compatible fabrics that can be used inconjunction with the present technique. In general, the structure andmaterial of the strip are selected based on an intended application ofthe product.

Referring back to FIGS. 1A and 1B, arms 112 are held in place against aninboard portion of flexible base 114 by an array of discrete bondedregions 118. As shown, each of the bonded regions is surrounded by anunbonded area of loop material. Bonded regions 118 can be formed, forexample, using a heat staking process (e.g., ultrasonic heat staking) tofuse the folded, overlapping layers of loop material together at variousdiscrete points. In this particular example, a single patterned band orrow of bonded regions 118 a extends along and overlaps the twolongitudinal edges 110 to form a seam that holds strip 108 in a folded,two-layer configuration. An additional pattern of bonded regions 118 bextends broadly over the other portions of the folded strip 108 tosecure arms 112 firmly in place against flexible base 114. Usingpatterned arrays of discrete bonded regions to secure the preform stripin a folded configuration can be advantageous in many differentapplications. In particular, this type of construction may provide moreflexibility than a similar strap, for example, where adhesives or a sewnseam are used to secure the folded outboard portions of the strip inplace. Moreover, the present technique offers a substantial amount ofair permeability so that the strap is “breathable” when in contact witha user's skin.

The outlining footprint of the bonded regions can vary between differentimplementations of the double-sided loop strap, so as to providestructurally different products. For example, the size of the bondedregions may differ from one application to the next. With other factorsbeing equal, larger bonded regions will provide the strap morestructural stability and bond strength than will smaller bonded regions.However, the stability and strength provided by the larger bondedregions comes at the cost of reduced flexibility, air permeability, andclosure performance (e.g., shear, tensile, and peel strength). Inparticular, the reduction in closure performance is a result of thereduced loop material available for hook engagement, as the loops arepressed down and fused in the bonded regions. Similarly, the patterndensity of the bonded regions can be a significant variable betweendifferent implementations. In particular, a denser pattern of bondedregions will tend to provide more dimensional stability and bondstrength, while offering less flexibility, air permeability and closureperformance. Generally, the above-described physical properties willvary according to a ratio comparing the total area of bonded regions tothe total unbonded area of the strap. That is, structural stability andbond strength will increase when the total area of the bonded regionsincreases relative to the total unbonded area. On the other hand,flexibility, air permeability, and closure performance will increasewhen the total unbonded area increases relative to the total area of thebonded regions. Of course, various other properties of the loop strapmay also be affected by the configuration of the bonded regions.

Referring again to FIGS. 1A and 1B, bonded regions 118 b are provided ina precise geometrically regular pattern of uniform density, whichprovides substantially consistent and isotropic physical propertiesacross strap 100. In some examples, however, the pattern of bondedregions is purposefully irregular to provide different physicalproperties around specific areas of strap 100, and/or to provide somedirectionality to these physical properties.

FIG. 2A shows an example where bonded regions 118 b′ are established inan irregular pattern. In particular, the pattern density of the bondedregions gradually increases from the center area of the strap in thedirection of the outboard folds. In this embodiment, strap 100′ would bestronger and stiffer at the outboard areas and more flexible andbreathable near the center. Additionally, peel strength would be greaternear the center of the strap than around the outboard areas, becausethere is more loop material available for hook engagement. FIG. 2B showsan example where bonded regions 118 b″ are established in anotherirregular pattern, where the distance between the bonded regions issmaller in the widthwise direction of the strap than in the lengthwisedirection. In this case, strap 100″ would be more flexible in thelengthwise direction and more rigid in the widthwise direction.

As noted above, the row of bonded regions 118 a overlaps edges 110 toform a seam along the back side 102 of strap 100. In the previousexamples, bonded regions 118 a are generally circular and distributed ata constant interval along longitudinal edges 110. FIG. 3 shows anexample where bonded regions 118 a′″ are provided in different types ofshapes, so as to form a visually distinguishable graphic. In thisembodiment of strap 100′″, bonded regions 118 a′″ are shaped asindividual letters “V”, “E”, “L”, “C”, “R”, and “O”. Numerous types ofshapes can be used to form graphic images such as for logos, brandnames, and the like. FIG. 3 also provides an example where the bondedregions near the center area of the strap cover a greater area than thebonded regions near the outboard folds. This type of configuration wouldprovide more bond strength and rigidity near the seam, the part of thestrap offering the least structural integrity.

FIGS. 4A and 4B show another embodiment of a double-sided loop strap200. Strap 200 is similar to strap 100 described above. For example,strap 200 is a two-layered construction presenting hook compatible loops206 on both a front side 204 and a back side 202 of the strap. In thisexample, strap 200 is a composite structure fashioned from two separatepreform strips of loop material 208 a and 208 b, each of which includesa flexible base 214 a,b bearing a field of upstanding loops 206 a,bextending from an outward surface bounded by free longitudinal edges 210a,b. The strips are similar, but provide different types of loops, withloops 206 a being presenting less loft than loops 206 b. As shown,longitudinal edges 210 a of strip 208 a are folded over flexible base214 a to meet the respective edges 210 b of strip 208 b. Two similarsets of discrete bonded regions 218 a are provided to secure therespective edges 210 a and 210 b in place against an inboard portion offlexible base 214 a. As shown, each set of bonded regions 218 a providesa row of regions extending along and overlapping the respective edges210 a and 210 b. Similar to the previous examples, a pattern of bondedregions 218 b extends broadly over other portions of strips 208 a and208 b to secure the strips in a tightly bound construction.

FIGS. 5A and 5B show yet another double-sided loop strap 300 having afront side 304 and a back side 302, each of which presents a field ofupstanding, hook compatible loops 306 facing outward therefrom. Similarto the previous examples, loop strap 300 is a two-layer constructionfashioned from a preform elongated strip of loop material 308 with freelongitudinal edges 310 folded over to form two inwardly facing arms 312.In particular, strip 308 includes a flexible base 314 bearing a field ofupstanding loops 306 extending from an outward surface bounded bylongitudinal edges 310.

In this example, a thin layer of resinous grip material 322 is depositedon an inboard portion of flexible base 314, on the back side of the baseopposite loops 306 (see FIG. 5C). Longitudinal edges 310 are folded overthe outer portions of the layer of grip material 322, such that outerportions of the layer of grip material are sandwiched between the twolayers of loop material, while the center portion remains exposedbetween edges 310. As shown, the exposed surface of the grip material isrecessed relative to the neighboring loop-bearing surface and bounded bythe longitudinal edges. In various implementations, the exposed gripsurface can have a lateral extent of between 10 and 90 percent of theoverall width of the strap. In general, the loop strap will exhibit moregripping ability when a greater amount of the grip surface is exposed.The additional grip would come at a cost of closure performance, as lessloop material is provided for engagement. Various implementations andapplications may necessitate different configurations of the strap withregards to the grip surface. For example, a strap designed for use onluggage may require nearly the entire surface to be grip material, anddoes not require breathability for comfort to the user. A strap utilizedto secure a knee brace may need very little grip material in order toprovide adequate security to the user, and will allow for more airmovement through the strap, to enhance the user's comfort.

In this embodiment, the folded longitudinal edges can be secured inplace using an appropriate adhesive, sewing or by heat staking, asdiscussed above. In some examples, the grip material itself serves as anadhesive, such that the folded edges are held in place against the basesolely by adhesion from the grip material.

Grip material 322 can have any appropriate composition so as to providea substantially non-slip surface. By “non-slip” surface, we refer to anysurface designed to inhibit or prevent a smooth slipping or slidingmotion by providing adequate surface friction. The grip material canprovide a relatively high coefficient of friction (e.g., a dynamiccoefficient of friction greater than about 0.3), and may be generally“soft” or “skin friendly” to the touch. For example, soft elastomers(e.g., styrenic block copolymers, such as styrene-isoprene-styrene,styrene isoprene/butadiene styrene, and styrene-butadiene-styrene),rubbers (e.g. flouroelastomers) or silicones can be used. Other suitablecompositions can also be used. For example, various plastics withmodified lower molecular weight constituents and thermoplasticelastomers (e.g., modified polypropylene or modified polyethylene) canserve as a grip material. In some examples, the grip material isparticularly well designed for skin contact, featuring a tack free,non-allergenic, and non-irritant composition.

FIGS. 6A and 6B show an additional example of loop strap 300′ where thelayer of grip material 322′ provides a pattern of molded, upstandingtreads 324 that provide additional surface friction for mitigating slip.In this example, the grip material includes three undulating treadsextending lengthwise down the strip. Of course, other appropriateconfigurations are also contemplated. For example, more or less treadscan be provided; the treads can extend widthwise across the strip (asopposed to lengthwise, see FIG. 8); the treads can be substantiallystraight (as opposed to undulating); and/or the height and thickness ofthe treads can vary.

FIGS. 7A and 7B show yet another example of loop strap 300″ where thedeposited grip material 322″ includes a foaming agent (e.g., a heatactivated foaming agent). In these examples, the loop strap is generallyconstructed as described above with reference to FIGS. 5A-5C. Afterconstruction, the foaming agent is activated to expand the layer of gripmaterial 322″, raising the exposed non-slip surface to be level with theneighboring loop material. In some examples, the non-slip surface israised above the loop material.

FIG. 8 shows an example implementation of a double-sided loop strap 400featuring an exposed non-slip surface having upstanding slip inhibitingtreads 424 formed of an appropriate grip material 422. In this case, theloop strap 400 is used in conjunction with a buckle 480 to form anadjustable cinch strap, such as may be used to support a medical orsports device on a user. The cinch strap is formed by threading afree-end 482 of loop strap 400 through buckle 480, wrapping the loopstrap around an object, re-threading the free-end back through thebuckle, and folding the strap back on itself. In this example, free-end482 provides a patch of loop compatible fasteners (e.g., hooks) toengage the loop material on either side of the grip material 422, thussecuring the strap in place.

As discussed above, the non-slip surface can be level or above thesurrounding loop material. In this case, the upstanding treads 424 canbe designed to engage one another when the strap is folded back onitself, impeding the ability of the strap to easily release back throughthe buckle, essentially creating a one-way cinch strap. If the gripconnection between both elements is designed with appropriate strengthfor the application, the uni-directionality, coupled with the presenceof the buckle, could even hold the strap in place, without the abovementioned loop compatible fasteners on the free-end of the strap. Insome examples, the non-slip surface is recessed relative to thesurrounding loop material. This configuration would render the loopstrap more comfortable when pressed against a user's skin and provideless interference with the buckle of the cinch strap. Either of theseabove described configurations may prove useful in various applications.

FIGS. 9A and 9B show another example loop strap 500 having a front side504 and a back side 502, each of which presents a field of upstanding,hook compatible loops 506. In particular, loop strap 500 is a two-layerconstruction fashioned from a preform elongated strip of loop material508 including a flexible base bearing a field of loops 506 and definingfree longitudinal edges 510, which are folded over to form two inwardlyfacing arms 512. Each of arms 512 defines a patterned set of discreteapertures 526 that extend entirely through the flexible base.

Similar to the previous examples, a thin layer of grip material 522 isdeposited on an inboard portion of the flexible base. However, in thiscase, longitudinal edges 510 are completely folded over the layer ofgrip material 522 to meet near a center portion of strip 508, such thatthe layer of grip material is entirely sandwiched between the two layersof loop material. As shown, apertures 526 are aligned with the gripmaterial 522 so as to leave various portions of the grip materialsurface exposed. The exposed surface of the grip material is recessedrelative to the neighboring loop-bearing surface and bounded by theedges of the apertures.

Several of the foregoing examples (shown in FIGS. 5A-9B) providedouble-sided loop straps that offer a substantially non-slip surface ofgrip material bounded by folded portions of a preform strip of loopmaterial. The folded portions of the loop material effectively hide theedges of the deposited resinous grip material, which may be unsightlyand rough because it can be difficult to produce a uniform resin edge.

FIG. 10A shows an example apparatus 628 which is suitable formanufacturing a double-sided loop strap 600, such as described above.Apparatus 628 receives a preform strip of loop material 608 provided inthe form of an elongated flexible substrate carrying a field ofupstanding loops on one side. Preform strip 608 is fed to a foldingdevice 630 that folds the longitudinal edges of strip 608 inward tooverlap an inboard portion of the flexible base. The folded, two-layerstrip is introduced to a heat staking machine 632 that creates theprescribed patterns of bonded regions by fusing the two layers ofmaterial together at various discrete points. The resulting double-sidedloop strap 600 is then spooled onto a final product roll 638.

The folding device and heat staking machine can be selected from a widevariety of conventional equipment. In the present example, heat stakingmachine 632 includes a patterned roller 634 having individualprojections extending from its outer surface, and a horn 636 forfacilitating the ultrasonic vibration with the folded strip 608 againstthe patterned roller.

FIGS. 10B-10E show how apparatus 628 can be adapted for forming anon-slip surface on the double sided loop strap by depositing gripmaterial on a back side of the preform strip of loop material prior tofolding. In FIG. 10B, a resin applicator 640 is positioned upstream offolding device 630. Resin applicator 640 extrudes a solid layer of gripmaterial onto the back of the loop surface prior to folding. The rollers634, 636 after the folding station can either be used to simply seal thefolded product utilizing the grip material as the bonding agent or couldbe ultrasonic welders to bond the fold in place (as described above). InFIG. 10C, resin applicator 640′ extrudes multiple strands of gripmaterial onto the back of the loop surface prior to folding. In FIG.10D, a resin applicator 640″ is designed to extrude dots of gripmaterial onto the back of the loop surface prior to folding. In FIG.10E, a roll of film based grip material 642 is placed on the back of theloop surface prior to folding. In this example, the film of gripmaterial includes an array of openings to improve breathability of thedouble-sided loop strap. The grip material, however, can also be a solidfilm or a film that includes micro perforations.

While a number of examples have been described for illustrationpurposes, the foregoing description is not intended to limit the scopeof the invention, which is defined by the scope of the appended claims.There are and will be other examples and modifications within the scopeof the following claims. For example, modifications could includepunching holes in the loop strip to further improve flexibility andbreathability of the double-sided loop strap.

What is claimed is:
 1. A method for forming a double-sided loop strap,the method comprising: receiving a continuous longitudinal strip of loopmaterial comprising a strip-form base bearing a field of upstandingloops on a fastening side of the strip bounded by opposite longitudinaledges; folding each of the longitudinal edges away from the fasteningside, such that the base overlaps itself; and securing the folded edgesin place by permanently bonding together overlapped areas of the base toform the double-sided loop strap, wherein the bonding forms discretebonded regions of the base surrounded by unbonded area, the bondedregions including a row of the bonded regions extending along andoverlapping at least one of the folded edges, and a pattern of bondedregions surrounded by engageable loops on either side of the strap. 2.The method of claim 1, wherein folding each of the longitudinal edgescomprises folding the edges sufficiently inward to meet on one side ofthe strap.
 3. The method of claim 1, wherein the row of bonded regionsforms a seam along the longitudinal edges.
 4. The method of claim 1,wherein the bonded regions of the row of bonded regions are shaped toform visually recognizable graphics.
 5. The method of claim 1, wherein adensity of the pattern of bonded regions varies widthwise and/orlengthwise along the strap.
 6. The method of claim 5, wherein thedensity of the pattern of bonded regions gradually increases from acenter area of the strap in an outboard direction.
 7. The method ofclaim 1, wherein permanently bonding comprises heat staking overlappedareas of the base.